The invention concerns a device for testing the beam-setting of motor vehicle headlights.
Testers the motor-vehicle headlight settings are needed to perform careful beam settings at short distances in motor vehicle shops at ordinary shop illumination. In principle the light of the headlight to be tested is projected on a test surface when using such testing devices, where the test surface is provided with markings for the standard setting and the tolerance limits. In devices of the state of the art the lens and the test surface are mounted within a common housing, an opening or window allowing the test operator to look at the test surface. The housing is mounted on a support where it can be adjusted in height by a handwheel in order to match the individually varying headlight beam height of the various vehicles. Most supports or tripods are equipped with foot screws allowing levelling the device by means of a box level mounted to it. Lastly the tripods are provided with wheels so that upon completion of the tests on one headlight, the device can be moved to the next and so that the device be mobile in the first place for instance between various sites within one motor vehicle shop.
The device's adjustability in height requires a rigid tripod with an elevation guide and a gear-rack mounted thereto, a pinion mounted on the handcrank engaging this gear rack. Compared to the simple optical operation, these devices incur a high mechanical cost, and the necessary rigid construction entails a substantial weight. As a result the costs of manufacture are relatively high. Furthermore the levelling procedure appears to be meaningful only if simultaneously the motor vehicle being tested is level as well.